New evidence suggests that nanoflares, small but potent bursts of energy, might heat the Sun’s outer atmosphere. But the evidence is still up for debate.
For decades, scientists have struggled to understand why the Sun’s outer atmosphere, known as the corona, is a blistering-hot few million degrees when its visible ‘surface ’ the photosphere, bubbles away far below at only thousands of degrees. Ideas range from waves rippling along magnetic field lines to field lines twisted so tightly they snap, releasing tremendous amounts of energy.
There’s also another question to answer: is the heating process steady, or does it occur in explosive bursts?
These bursts would be small stuff — they release only a billionth the energy of regular flares, and they d be too small, quick and faint for…